Air-conditioning apparatus



1952 N. E. BERRY 2,604,306

AIR-CONDITIONING APPARATUS Filed Oct. 17, 1946 37 INVENTOR.

Patented July 22, i952 AIR-CONDITIONING APPARATUS Norton E. Berry,Newburg, Ind, assignor to Servel, Inc., New York; N. Y., a corporationof Delaware Application Octoberli', 1946, Serial No. 703,737

3 Claims. 1

This invention relates to heating and cooling wherein the same heatexchanger serves as both a heater and a cooler.

The novelty resides in blocking the flow of vapor in a certain path offlow between a condenser and the heat exchanger when cooling is desired,whereby the vapor is condensed and the liquid produced thereby flows tothe heat exchanger through the certain path in suiilcient quantities todo a good cooling job; and in removing the blockage when heating isdesired, whereby a supply of hot vapor ample to do a good heating jobflows unrestricted to the heat exchanger through the certain path; allwithout the use of internal mechanical valves or the like in the fluidcircuits of the apparatus.

This invention, although not limited to, is particularly adapted forhousehold air conditioning. Therefore, an excellent manner of enjoyingthe invention is by employing a refrigerating apparatus oi theabsorption type, for instance, like that disclosed in Patent No.2,282,503 to A. R. Thomas and P. P. Anderson, Jr. Certain changes aremade in the Thomas et a1. apparatus which cause hot water vapor to flowto the evaporator at low pressure when heating is desired, and whichcause water to flow to the evaporator when cooling is desired.

The invention, together with its objects and advantages, is set forth inmore technical detail in the following description and the accompanyingdrawing in which the single figure shows more or less diagrammaticallyan apparatus for heating and 0001' g in accordance with this invention.1 4 7 Referring to'the drawing, the apparatus shown comprises basicallya two pressure water absorption type refrigerating unit generally asdescribed in the above Thomas and Anderson patent. An apparatus of thistype operates below atmospheric pressure and includes a generator ID, acondenser H, an evaporator l2 and an absorber M which are interconnectedin such a manner that, when operating as a cooling unit, flow of fluidbetween the highand low sides of the apparatus is regulated by liquidcolumns. By ccndenser.as applied to the element H is meant therefrigerant condenser or] liquefier for cooling operations. Byevaporator as applied to element i2 is meant the heat exchanger or aircontact coil which functions as an evaporator or cooling element duringcooling periods of operation, and as acondenser or heat radiator duringheating periodsof :operation.

The generator 10 includes an outer shell within which are disposedaplurality of vertical riser tubes [6 having the lower ends thereofcommunicating with an inlet chamber 11 and the upper ends thereofextending into and above the bottom of a separating vessel It. A spaceI9 within shell 15 and about the tubes iii forms a steam chamber towhich steam is supplied through a conduit 20. Steam issupplied tochamberlfi at suitable"pressures, -so thatthe apparatus may operate'as a"heating unit as well as a cooling unit. Condensate formed in steamchamber i2 is withdrawn therefromthrough. a conduit 2 i. v

The apparatus contains a water solutionofr'eirigerant in absorbentliquid such as, for example, a water solution of lithium chloride orlithium bromide or a mixture of the two. With steam supplied throughconduit 20 to space [9, heat is applied to tubes 16 whereby water vaporis expelled from solution. The residueabsorption solution is raised bygas or vapor-lift action with the expelled water vapor forming a smallcore within an upwardly rising annulus oi the solution. The expelledwater vapor rises more rapidly than the solution with the solutionflowing along the inside walls of the tubes Ill.

The water vapor flows upwardly through the tubes or risers I 6 intoseparating vessel l3 wherein the water vapor is separated from theraised absorption solution and flows through a conduit 22 into condenserll wherein the vapor isv condensed. The liquid refrigerant formed incondenser ii flows through a U-tube 23 and an orifice 25 into a flashchamber or separating vessel 28. The liquid refrigerant flows from theflash chamber through a conduit 21 into a distributing trough 2'5 andfrom there into tubes 29 of the evaporator. A second U-tube or trap 35),to be referred to in more detail hereinafter, is connected between thelower portion of U-tube 23 and the lower portion of flash chamber 26. Avapor conduit 3| leads from the upper part of flash chamber 28 into aheader 32 of the evaporator. The refrigerant evaporates in evaporator !2with consequent absorption of heat to produce a refrigerating effectwhich is utilized to cool an air stream flowing over the tubes 29. Tubes29 are provided with heat transfer fins 34.

The refrigerant vapor formed in evaporator l2 flows into headers 32 ateach end of the evaporator and from there to the absorber M in which thevapor is absorbed by the absorption solution which enters the upper partof the absorber through a conduit 35. The absorption solutionenriched'in refrigerant is conducted from absorber [4 through a conduit36, an inner passage in a liquid heat exchanger 31, a conduit 38, astabilizing vessel 39, and a conduit 40 into chamber ll of generator l0.Refrigerant vapor is expelled out of solution in generator ill byheating, and the solution is raised by gas or vapor-lift action in risertubes 16, as explained above.

The absorption solution weak in refrigerant which has been lifted in theriser tubes l6 into vessel 18 flows therefrom through a conduit 4|, anouter passage in liquid heat exchanger 31, and conduit 35 into the upperpart of absorber I4. This circulation of absorption solution resultsfrom the raisingof solution in riser tubes IB, whereby such solutionflows to the absorber and returns from the latter to the generator byforce of gravity. Vessel 39 and vessel [8 are connected by a ventconduit 42.

When the apparatus is operating as a cooling unit, the absorber l4 andcondenser ll constitute heat rejecting parts of the apparatus and arecooled by a suitable cooling medium such as water, for example, which isconducted from a suitable source of supply through a conduit 43 to abank of tubes 44 within the absorber, whereby heat of absorption isgiven up to the cooling water. The cooling water is conducted from theabsorber through a conduit 45 to condenser l l in which heat ofcondensation is given up to the cooling water. The cooling water leavesthe condenser through a conduit 46. Conduit 43 is provided with a valve41 for cutting off the supply of cooling water to the absorber andcondenser during heating periods of operation.

In operation, whena cooling cycle is first started following a shut-downon a heating cycle only a small quantity of liquid is contained in traps23 and 30. However, with cooling water flowing to the condenser thepressure therein is such that orifice 25 offers an appreciableresistance to vapor flow therethrough at this condenser pressure, withthe result that some vapor begins to condense in the condenser and thiscondensate is carried along with vapor to trap 23. Part of thecondensate will separate from the vapor at the bottom of trap 23 andflow into trap 30 and part will be carried through the upleg of trap 23into flash chamber 26 wherein this portion of the condensate willseparate from the vapor and flow downward in trap 30 and into the bottomof trap 23 resulting in an accumulation of condensate in traps 23 and30. Any condensate that passes through orifice 25 with vapor at thestart of a cooling cycle will add to the resistance to flow of vaporthrough the orifice. With the resistance to vapor flow set up in theorifice and the resistance offered by the accumulated liquid in U- traps23 and 30, pressure balancing liquid columns are soon establishedbetween the condenser and the flash chamber so that no more vapor passesfrom the condenser to the flash chamber. Orifice 25 is of such size thatit offers substantially no resistance to liquid flow therethrough, butonce liquid starts flowing through this orifice, as when cooling Wateris supplied to the condenser and some vapor is condensed therein, theresistance to vapor flow therethrough is appreciably increased. Once thetraps 23 and 30 have been filled with liquid they stay filled so long asthe apparatus is operating on normal or high load cooling cycles.

} To shift from a cooling cycle to a heating cycle all that is necessaryis to cut off the supply of cooling water to the condenser and absorberby closing the valve 41 in conduit 43. With the supply of cooling watercut oil. from the absorber and condenser, the condenser pressure risesrapidly and to the extent that trap 30 is first blown free of liquid,following which trap 23 is blown free of liquid, and hot refrigerantvapor flows at this increased pressure substantially unrestricted fromthe condenser through trap 23, orifice 25,v flash chamber 26 and vaporconduit 3| into header 32 at the right of the evaporator. The evaporator now serves as a heat radiator or condenser wherein the hot vaporflows through tubes 29 in which the vapor is condensed giving up itsheat of condensation to air flowing over the tubes. The condensateformed in the evaporator flows into the absorber and from there isreturned to the generator. On a heating cycle, once the traps 23 and 30are blown free of liquid they remain substantially free during theheating cycle.

Under certain conditions of operation on cooling cycles, flow ofcondensate from the condenser may fall below a certain minimum wherebythe normal pressure differential between the condenser and theevaporator is not maintained. Under these conditions hot condensate maybegin to flash at the top of the upleg of trap 23. This flashing maycontinue in trap 23 thus decreasing the density of the fluid in theupleg of this trap causing the level of liquid to fall in the downlegthereof until the trap is broken and vapor from the condenser leaksaround through the trap and finally reaches the evaporator. Trap 30 isprovided to take care of flashing in the upleg of trap 23. With thearrangement illustrated in the drawing, any decrease in density of fluidin the upleg of trap 23 will cause liquid to flow down through trap 30and into trap 23. This will increase the ratio of liquid to vapor in theupleg of trap 23 thus increasing the density of the fluid at this point.This increase in density will increase both the hydrostatic and velocityhead on the upleg of trap 23 sufficiently to prevent the level in thedownleg of this trap from falling to the bottom of the trap. Thecondensate in the downleg in trap 23 will in fact seek a level such thatthe difference in inches be" tween this level and the level at the topof the upleg of this trap will be approximately equivalent to thedifference in vapor pressure between the condenser and flash chamberexpressed in inches of water.

The conduit which forms trap 30 has an internal cross-sectional area sosmall as to present sufficient resistance to vapor flow therethroughwhen no liquid is contained therein that together with the resistanceprovided by orifices 25, vapor will be caused to condense in thecondenser upon shifting from a heating to a cooling cycle. Trap 30, onthe other hand, ofiers substantially no resistance to the flow of liquidtherethrough. Also, as stated above, any condensate that is carriedthrough the upleg of trap 23 into flash chamber 26 will separate fromthe vapor and return through trap 30 into the bottom of trap 23, thusgradually building the equivalent of a liquid column in trap 23. Thus itis seen that trap 30 performs two important functions: (1), acceleratesthe filling of trap 23 when the apparatus is shifted from a heating to acooling cycle; and (2), maintains trap 23 filled with fluid which is theequivalent of a liquid column during cooling cycle operations.

Having thus described my invention, I wish it to be understood that I donot desire to be limited to the exact details of construction shown anddescribed, for obvious modifications will occur to a person skilled inthe art.

What is claimed is:

l. A heating and cooling apparatus comprising an absorptionrefrigerating system of the two pressure type having a still comprisinga generator and a liquefier in the high pressure side, an absorber and aheat exchanger in the low pressure side, the heat exchanger serving asan evaporator or cooling element during cooling periods of operation andas a condenser or heat radiator during heating periods of operation, andconduits interconnecting said elements to provide circuits for flow of arefrigerant fluid and an absorption liquid, said conduits including aliquid trap in a conduit between said liquefier and said heat exchangerutilizing a body of liquid to bar flow of vapor from the high side tothe low side during cooling periods of operation and so constructed andarranged that the body of liquid is displaced to permit flow of vapor toeffect a heating period of operation upon increase in pressure in thehigh side as by termination of heat removal from said liquefier, and aliquid collecting chamber also in said conduit between said trap and theheat exchanger and connected by a further conduit to said liquid trap topromote reforming of said body of liquid upon decrease in pressure inthe high side by delivering liquid at a rate greater than the rate ofsupply of liquid from said liquefier upon such pressure decrease.

2. A heating and cooling apparatus comprising an absorptionrefrigerating system of the two pressure type having a still comprisinga generator and a liquefier in the high pressure side, an absorber and aheat exchanger in the low pressure side, the heat exchanger serving asan evaporator or cooling element during cooling periods of operation andas a condenser or heat radiator during heating periods of operation, andconduits interconnecting said elements to provide circuits for flow of arefrigerant fluid and an absorption liquid, said conduits including aliquid trap in a conduit between said liquefier and said heat exchangerutilizing a body of liquid to bar flow of vapor from the high side tothe low side during cooling periods of operation and so constructed andarranged that the body of liquid is displaced to permit flow of vapor toeffect a heating period of operation upon increase in pressure in thehigh side as by termination of heat removal from said liquefier, and aliquid accumulating chamber also in said conduit between said trap andsaid heat exchanger and connected by a further conduit to said trap, andsaid conduit has a liquid flow restricting orifice between said trap andsaid chamber to promote reforming of said body of liquid upon decreasein pressure in the high side by delivering liquid at a rate greater thanthe rate of supply of liquid from said liquefier upon such pressuredecrease.

3. A heating and cooling apparatus comprising an absorptionrefrigerating system of the two pressure type having a still comprisinga generator and a liquefier in the high pressure side, an absorber and aheat exchanger in the low pressure side, the heat exchanger serving asan evaporator or cooling element during cooling periods of operation andas a condenser or heat radiator during heating periods of operation, andconduits interconnecting said elements to provide circuits for flow of arefrigerant fluid and an absorption liquid, said conduits including aliquid trap in a conduit between said liquefier and said heat exchangerutilizing a body of liquid to bar flow of vapor from the high side tothe low side during cooling periods of operation and so constructed andarranged that the body of liquid is displaced to permit flow of vapor toeffect a heating period of operation upon increase in pressure in thehigh side as by termination of heat removal from said liquefier, and aliquid holding container connected by a further conduit to said trap topromote reforming of said body of liquid upon decrease in pressure inthe high side by delivering liquid at a rate greater than the rate ofsupply of liquid from said liquefier upon such pressure decrease.

NORTON E. BERRY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,019,290 Brace Oct. 29. 19352,064,040 Smith Dec. 15, 1936 2,365,797 Bichowski Dec. 26, 19442,368,455 Edberg Jan. 30, 1945

